1. Field of the Invention
The present invention relates to the field of use of telecommunications. More particularly, the present invention relates to enhancing the usability of faxes and other image transmissions for display on small screens such as the display of a Personal Digital Assistant or handheld computer or other devices having a limited display and/or limited storage capacity.
2. Description of Related Art
Image and text data transmitted by fax machines are among the most widespread new uses of voice and data communications devices such as telephones. These faxed images are usually transmitted through the telephone and received for printout or storage of the image on a destination fax machine or computer for the use of the recipient. Since the destination machine has typically been a fax, computer, printer or other such large capacity storage and output device, there has not been a need to compress the fax significantly for the destination output device. Furthermore, scaling of the fax to fit small hand-held viewscreens has not been necessary since the traditional destination has been either a full size print-out, computer monitor or mass storage media.
With the ongoing development of devices such as Personal Digital Assistants (PDAs) having small graphical viewscreens, the display and handling schemes for fax images must be adapted to overcome the limitations of such devices if they are to adequately receive fax transmissions. Though equipped with graphical viewscreens, these PDAs, unlike their fax machine or computer counterparts, have extremely limited storage and video capabilities. For instance on a PDA, the typical storage space totals only one megabyte (1 MB), and this space would be quickly filled by just six pages of fax data which would total 900 Kilobytes (900 KB).
Devices such as PDAs or handheld computers have the ability to receive fax information even though they are used primarily to send out faxes. But using such a device, the recipient must scroll through portions of the faxed document image, or receive the fax in parts and is unable to receive several pages or multiple faxes at once due to storage limitations. Thus, there is an urgent need for compressing incoming fax transmissions before they are finally viewed by the recipient on the destination PDA and display. Further, since the screen size is small compared to normal displays and as compared with the fax, there is a need to efficiently scale the image to avoid the recipient having to scroll through the image once it is received.
Many techniques are known and have been developed to scale and compress images but these techniques are usually too compute intensive for a PDA which has no significant memory system nor microprocessor capability compared to a desktop computer. Further, these compression and scaling schemes have never been adapted to transmit a fax such that it be adequately displayed on a very small display screen like a PDA display screen. Rather, many of the techniques used rely on scaling and compressing the entire image pixel-by-pixel as a bitmap and do not optimize for a fax document which is largely text with some image data. Thus, there is required a system and method for compressing and scaling fax images for the specific purpose of efficiently receiving and displaying them on PDA display screens or other small device screens with limited microprocessor and storage capability.